基于LCCL滤波器的三相并网逆变器前馈控制策略

在dq旋转坐标系下提出了基于LCCL滤波的三相并网逆变器前馈控制策略,该控制策略可以有效抑制电网电压畸变造成的并网电流谐波。首先在dq坐标系下分析了基于LCCL滤波的三相并网逆变器控制策略的优点,但在该控制策略下,网侧电流没有直接受控导致其对于电网电压畸变的抑制能力较差,这将造成网侧电流较大的谐波。通过推导闭环系统中网侧电压与给定量之间的关系,完全前馈电网电压以减小电网电压畸变对网侧电流的影响,同时分解前馈量,分别前馈至电流给定以及控制量上从而增加了该前馈策略的可行性。最后,仿真以及100kW样机的实验结果验证了该方法的有效性。

A Feed Forward control Strategy For Three-phase Grid-connected Inverter with LCCL Filter

In this paper, a novel grid voltage feed forward control strategy under d-q rotating frame is proposed based on grid-connected three phase voltage source inverter with LCCL filter to suppress the grid current harmonics caused by the grid voltage distortion. Although the control strategy of grid-connected inverter with LCCL filter has many advantages, this control strategy fails to control grid current directly making the current sensitive to the grid voltage distortion. This paper analyzes the impact from grid voltage to the grid current on d-q rotating frame. Then a feed forward component of grid voltage is derived to completely eliminate the grid voltage impact on grid current. To make this scheme applicable, an equivalent strategy in which grid voltage feed forward components are separately inserted into current reference and modulation is proposed. The results of both simulation and experiment of 100kW prototype verify the effectiveness of the proposed scheme.